The WD Se rounds out WD's expansive range of storage solutions for the datacenter. The WD Se is designed to aDDRess the need for high capacity scale out storage in replicated and NAS environments, providing a more economical method of storing large amounts of data. (NASDAQ:WDC)

Test System and Methodology

We utilize a new approach to HDD and SSD storage testing for our Enterprise Test Bench, designed specifically to target long-term performance with a high level of granularity.

Many testing methods record peak and average measurements during the test period. These average values give a basic understanding of performance, but fall short in providing the clearest view possible of I/O QoS (Quality of Service).

'Average' results do little to indicate the performance variability experienced during actual deployment. The degree of variability is especially pertinent, as many applications can hang or lag as they wait for I/O requests to complete. This testing methodology illustrates performance variability, and includes average measurements, during the measurement window.

Consistent latency is the goal of every storage solution, and measurements such as Maximum Latency only illuminate the single longest I/O received during testing. This can be misleading, as a single 'outlying I/O' can skew the view of an otherwise superb solution. Standard Deviation measurements consider latency distribution, but do not always effectively illustrate I/O distribution with enough granularity to provide a clear picture of system performance. We use histograms to illuminate the latency of every single I/O issued during our test runs.

We measure power consumption during test runs. This provides measurements in time-based fashion, with results every second, to illuminate the behavior of power consumption in steady state conditions. Power consumption can cost more over the life of the device than the initial acquisition price of the hardware itself. This significantly affects the TCO of the storage solution. We also present IOPS-to-Watts measurements to highlight the efficiency of the storage solution.

Our test pool features HDDs of varying capacity, so it is important to bear this in mind when viewing results. We conduct our tests over the full LBA range to allow each HDD to highlight its top performance. In some cases, this approach can give slower speed, and higher capacity, HDDs a slight advantage in test results due to a longer 'dwell' time on outer tracks. Typically, this is not a concern when testing HDDs of similar speeds and capacities. The first page of results will provide the 'key' to understanding and interpreting our new test methodology.